1. Field of the Invention
The present general inventive concept relates to a developer supply and recovery system used with a wet electro-photographic image forming apparatus, and more particularly, to a developer supply and recovery system used with a wet electro-photographic image forming apparatus, and a developer supply and recovery method using the same, in which whether a developer supply unit and a developer recovery unit are normally operated before printing is sensed, and a noise generated from the recovery unit is reduced during printing.
2. Description of the Related Art
In a wet electro-photographic image forming apparatus, a charge unit charges a surface of a photosensitive medium, and the charged surface of the photosensitive medium is exposed to light radiated from an exposure unit depending on a print signal to form an electrostatic latent image. An image is formed from the electrostatic latent image using a developer supplied from a development unit, and then a transfer belt transfers the formed image onto a print medium, thereby obtaining a desired image.
The wet electro-photographic image forming apparatus employs a contact charge way in which the charge unit is in contact with the photosensitive medium to form an electrical potential on the surface of the photosensitive medium. A difference in electrical potentials applied to the respective units is used to attach the developer to the electrostatic latent image formed on the photosensitive medium or to transfer the image from the photosensitive medium to the transfer belt or from the transfer belt to the print medium.
Further, the wet electro-photographic image forming apparatus includes a development roller to attach the developer to the electrostatic latent image formed on the photosensitive medium, and a developer supply and recovery system to supply the developer to a development roller and to recover a remaining developer.
FIG. 1 is a view illustrating a conventional developer supply and recovery system of a wet electro-photographic image forming apparatus.
Referring to FIG. 1, a developer supply and recovery system includes an ink cartridge 10 for storing a developer therein, a supply line 11 for connecting the ink cartridge 10 with a development bath 14, a supply pump 12 installed on a supply line 11 to supply the developer from the ink cartridge 10 to the development bath 14, a recovery line 17 for connecting the ink cartridge 10 with a developer container 13 for temporarily containing the developer overflowing from the development bath 14, and a recovery pump 18 installed on the recovery line 17 to recover the developer contained in the developer container 13 to the ink cartridge 10.
The development bath 14 includes a development roller 16 and a photosensitive drum 15 at an upper side thereof. The development roller 16 is installed to have one portion thereof dip into the developer of the development bath 14 such that the stored developer is supplied to the photosensitive drum 15 having an electrostatic latent image formed thereon. The photosensitive drum 15 is installed to rotate in contact with the development roller 16 while developing the electrostatic latent image with the supplied developer.
An operation of the above-constructed developer supply and recovery system will be described.
If the supply pump 12 is operated, the developer stored in the ink cartridge 10 flows into the development bath 14 through the supply line 11, and the developer supplied to the development bath 14 is transferred to the photosensitive drum 15 by the development roller 16 to develop the electrostatic latent image formed on the photosensitive drum 15.
In the meantime, the developer not supplied to the photosensitive drum 15 by the development roller 16 overflows from the development bath 14, and is then contained in the developer container 13. The developer contained in the developer container 13 is recovered by the recovery pump 18 to the ink cartridge 10 through the recovery line 17 provided at a bottom side of the developer container 13 to be re-supplied to the development bath 14 through the supply line 11, thereby maintaining a print operation.
However, since the conventional developer supply and recovery system cannot exactly perceive states of the supply line 11, the supply pump 12, the recovery line 17 and the recovery pump 18, it cannot perceive whether or not the developer normally flows from the development bath 14 to the ink cartridge 10.
Accordingly, the conventional developer supply and recovery system has drawbacks in that if the supply line 11 and the supply pump 12 malfunction, the developer is not smoothly supplied to the development roller 16, thereby causing the electrostatic latent image not to be developed, and if the recovery line 17 and the recovery pump 18 malfunction, the developer overflows from the development bath 14 such that the developer contained in the developer container 13 is not recovered but overflows from the developer container 13, thereby polluting image forming apparatuses.
Further, the conventional developer supply and recovery system has drawbacks in that if the recovery pump 18 is not exactly controlled, the recovery pump 18 operates to recover the developer in a state where the developer does not exist at the developer container 13. That is, in a state where an inlet of the supply line 17 is not completely dipped into the developer contained in the developer container 13, air is introduced into the recovery line 17 together with the developer, thereby causing noise. The noise occurs because an amount of the developer contained in the developer container 13 is not appropriately controlled.